Fig. 3
The effect of different compounds on CSC population in A549 cell line. a and b Sphere-reformation assay. The A549 cells formed spheres after cultured in stem cell medium for 7 days. The spheres were exposed to S-Me-DDC (10 μM), Cu-DDC (5 μM), DDC (1 μM), TMDS (1 μM) and DS (1 μM) in combination with or without CuCl2 (10 μM) for 6 h. The spheres were trypsinized and cultured in drug free SCM at a density of 5000 cells/well in ultralow attached 24-well plates for another 7 days. The sphere numbers in each well were counted. c and d The effect of different treatments on ALDH activity in sphere cells. The spheres were trypsinized and exposed to different treatments for 6 h before ALDEFLUOR analysis. e and f The effect of different treatments on CD44 expression in sphere cells. n = 3, ** < 0.01